1. Field of the Invention
The present invention relates generally to integrated power conversion systems and methods for use in a variety of applications, such as battery-powered (electric) vehicle applications, fuel cell vehicle applications, and hybrid electric vehicle applications.
2. Description of the Related Art
Traditionally, the power conversion system of a battery-powered electric vehicle (EV), a fuel cell vehicle, and a hybrid electric vehicle (HEV) has included a plurality of separate, discrete components and assemblies. Among these components and assemblies are a traction inverter module (TIM) and a DC/DC converter.
The TIM, also called the electric power inverter, is operable for converting the raw DC current generated by a high-voltage fuel cell or high-voltage storage device (e.g., battery, flywheel, or ultracapacitor) into an AC current capable of powering an electric motor, such as a traction motor or a field-oriented induction motor. This power is converted for driving and controlling the motor, i.e., for generating torque. The motor, in combination with a transaxle, converts the electrical energy into mechanical energy which turns the wheels of the vehicle.
The DC/DC converter utilizes pulse-width modulation (PWM) to step the voltage associated with the vehicle's high-voltage battery or fuel cell down to that which the alternator of an internal combustion engine (ICE)-powered vehicle would typically generate (13.5–14V). The DC/DC converter, which may be unidirectional or bi-directional, may be used, for example, to charge a 12V auxiliary battery, which is typically separated from the high-voltage battery or fuel cell.
The DC/DC converter may also be used to transfer power from the auxiliary battery to the high-voltage battery or fuel cell to, for example, start the vehicle. In general, the DC/DC converter is operable for matching a plurality of voltages.
Traditionally, the TIM and the DC/DC converter are separate, discrete assemblies, including a 3-phase assembly for the TIM and an H-bridge assembly for the DC/DC converter. The TIM and the DC/DC converter have typically utilized separate, discrete high-voltage DC bus capacitors, DC bus bars, and high-voltage transistors. This configuration has several important limitations. High-voltage cables must be utilized to connect the TIM and the DC/DC converter. Separate, discrete thermal management systems must be utilized to cool the TIM and the DC/DC converter. The result is a complex, bulky, costly configuration. Thus, what is needed are systems and methods for integrating the TIM and the DC/DC converter.